The present invention relates to components for a substrate processing chamber.
In the processing of substrates, such as semiconductor wafers and displays, a substrate is placed in a process chamber and exposed to an energized gas to deposit, or etch material on the substrate. During such processing, process residues are generated and can deposit on internal surfaces in the chamber. For example, in sputter deposition processes, material sputtered from a target for deposition on a substrate also deposits on other component surfaces in the chamber, such as on deposition rings, shadow rings, wall liners, and focus rings. In subsequent process cycles, the deposited process residues can “flake off” of the chamber surfaces to fall upon and contaminate the substrate.
To reduce the contamination of the substrates by process residues, the surfaces of components in the chamber can be textured. Process residues adhere better to the exposed textured surface and are inhibited from falling off and contaminating the substrates in the chamber. The textured component surface can be formed by coating a roughened surface of a component, as described for example in U.S. Pat. No. 6,777,045 to Shyh-Nung Lin et al, issued on Aug. 17, 2004, and commonly assigned to Applied Materials, and U.S. application Ser. No. 10/833,975 to Lin et al, filed on Apr. 27, 2004, and commonly assigned to Applied Materials, both of which are herein incorporated by reference in their entireties. Coatings having a higher surface roughness can be better capable of accumulating and retaining process residues during substrate processing, to reduce the contamination of the substrates processed in the chamber.
However, the extent of the surface roughness provided on the coatings can be limited by the bonding properties of the coating to the underlying component structure. For example, a dilemma posed by current processes is that coatings having an increased surface roughness, and thus improved adhesion of process residues, also are typically less strongly bonded to the underlying structure. This may be especially true for coatings on components having a dissimilar composition, such as for example aluminum coatings on ceramic or stainless steel components. Processing of substrates with the less strongly adhered coating can result in delamination, cracking, and flaking-off of the coating from the underlying structure. The plasma in the chamber can penetrate through damaged areas of the coating to erode the exposed surfaces of the underlying structure, eventually leading to failure of the component. Thus, the coated components typically do not provide both adequate bonding and good residue adhesion characteristics.
Thus, it is desirable to have a coated component and method that provide improved adhesion of process residues to the surface of the component, substantially without de-lamination of the coating from the component. It is further desirable to have a coated component and method that provide a well-bonded coating having an increased surface roughness to improve the adhesion of process residues.